Method and apparatus for broadcast primitive filtering in SAS

• US 8,116,226 B1
• Filed: 01/30/2006
• Issued: 02/14/2012
• Est. Priority Date: 01/28/2005
• Status: Active Grant

• Current Assignee: Microsemi Solutions (U.S.), Inc. (Microchip Technology Incorporated)
• Original Assignee: PMC-Sierra Incorporated (Microchip Technology Incorporated)
• Inventors: Liao, Heng, Carr, Larrie Simon
• Primary Examiner(s): HSU, ALPUS
• Application Number:
  US11/341,574
• Time in Patent Office: 2,206 Days
• Field of Search: 370/254, 370/395.31, 370/401, 370/409, 709/220, 709/225, 709/229, 709/238, 709/250, 710/2, 710/36, 710/316
• US Class Current: 370/254
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272

Abstract

Broadcast primitive filtering in a SAS expander using virtual domains. The virtual domains can be non-overlapping or overlapping logical subsets of the physical topology, or a logical construct based on the membership of a device within a group. Broadcast event propagation is handled in accordance with predetermined policies associated with the virtual domains. These policies can, for example, include limiting the broadcast traffic within the boundaries of the logical zones defined by the subsets, or routing the broadcast events in accordance with access policies, or privileges, associated with the group.

Claims

1. A method for broadcast primitive filtering, comprising:

defining, based on expander phy, a first virtual domain and a second virtual domain within a serial attached small computer system interface (SAS) domain topology;

receiving, at a first serial management protocol (SMP) target port of the first virtual domain, a broadcast primitive from a source physical layer device within the first virtual domain; and

transmitting the broadcast primitive only to a plurality of physical layer devices in the first virtual domain according to a policy associated with the first virtual domain, the broadcast primitive comprising a four character code sequence, the primitive not containing header, address or payload information, the policy defining whether the source device is allowed to access a destination device, wherein the SMP target port determines a routing for the broadcast primitive, based on routing table resources.

2. The method of claim 1, wherein the source physical layer device is a source phy and the plurality of physical layer devices are phys.

3. The method of claim 2, wherein defining the first virtual domain and the second virtual domain comprises defining a plurality of logical zones within the SAS domain topology.

4. The method of claim 3, wherein transmitting the broadcast primitive includes transmitting the broadcast primitive to the phys associated with a logical zone.

5. The method of claim 4, wherein defining the first virtual domain and the second virtual domain includes associating each phy in the SAS topology to at least one of the logical zones.

6. The method of claim 4, wherein defining the first virtual domain and the second virtual domain includes associating at least one phy to multiple logical zones.

7. The method of claim 6, wherein receiving the broadcast primitive includes receiving zone membership information from the at least one phy.

8. The method of claim 1, wherein receiving the broadcast primitive includes receiving a broadcast primitive processor (BPP) request message.

9. The method of claim 1, wherein transmitting the broadcast primitive includes transmitting a broadcast primitive processor (BPP) transmit indication signal.

10. The method of claim 2, wherein defining the first virtual domain and the second virtual domain comprises associating phys in the SAS topology to device groups defined by group identification information.

11. The method of claim 10, wherein receiving the broadcast primitive includes receiving a broadcast frame including the broadcast primitive and the group identification information associated with the source phy.

12. The method of claim 10, wherein receiving the broadcast primitive includes receiving the broadcast primitive at an ingress expander phy and associating the group identification information associated with the source phy to the broadcast primitive.

13. The method of claim 10, wherein transmitting the broadcast primitive includes transmitting the associated group identification information.

14. The method of claim 12, wherein transmitting the broadcast primitive includes transmitting the broadcast primitive from an egress expander phy after removing the associated group identification information.

15. The method of claim 10, wherein the policy associated with the first virtual domain is a device group access policy.

16. The method of claim 15, wherein the device group access policy includes a policy matrix.

17. The method of claim 15, wherein the policy is configured by a source device or an expander.

18. A serial attached small computer system interface (SAS) expander device, comprising:

a plurality of ports, each port having at least one phy;

a plurality of phys, the plurality of phys being a subset of the phys associated with the plurality of ports, the plurality of phys being associated with a serial management protocol (SMP) target port of a virtual domain defined within a SAS topology, the virtual domain being defined based on expander phy; and

a broadcast primitive processor (BPP) for managing broadcast primitive propagation between the plurality of phys via the SMP target port within the virtual domain according to a policy associated with the virtual domain, the broadcast primitive comprising a four character code sequence, the primitive not containing header, address or payload information, the policy defining whether a source phy is allowed to access a destination phy, wherein the SMP target port determines a routing for the broadcast primitive, based on routing table resources.

19. The SAS expander device of claim 18, wherein the virtual domain is a logical zone defined within the SAS topology, and the BPP function is associated with a virtual expander associated with the logical zone.

20. The SAS expander device of claim 19, wherein the BPP includes means to limit broadcast primitive propagation to the logical zone.

21. The SAS expander device of claim 18, wherein the BPP includes a configuration register for storing zone membership information for a phy.

22. The SAS expander device of claim 18, wherein BPP request and indication messages include zone information associated with a source phy.

23. The SAS expander device of claim 18, wherein the virtual domain is defined based on group membership of phys within the SAS topology, and the BPP function includes means to manage broadcast primitive propagation in accordance with a device group access policy.

24. A serial attached small computer system interface (SAS) topology to permit broadcast primitive filtering, comprising:

a plurality of host and target devices, each including at least one phy;

at least one expander for interconnecting the plurality of host and target devices;

a virtual domain defined within the topology;

the virtual domain having logically associated therewith a serial management protocol (SMP) target port and a plurality of phys, the plurality of phys being a subset of the phys associated with the plurality of hosts and target devices, the virtual domain being defined based on expander phy; and

a broadcast primitive processor (BPP) for managing propagation of a broadcast primitive from any of the host and target devices to the plurality of phys via the SMP target port according to a policy associated with the virtual domain, the broadcast primitive comprising a four character code sequence, the primitive not containing header, address or payload information, the policy defining whether a host device is allowed to access a target device, wherein the SMP target port determines a routing for the broadcast primitive, based on routing table resources.

25. The SAS topology of claim 24, wherein a plurality of virtual domains are defined within the topology.

26. The SAS topology of claim 25, wherein the plurality of virtual domains are a plurality of logical zones comprising separate subsets of phys.

27. The SAS topology of claim 26, wherein the plurality of logical zones are non-overlapping.

28. The SAS topology of claim 26, wherein the plurality of logical zones are overlapping.

29. The SAS topology of claim 26, wherein the BPP restricts propagation of the broadcast primitive to one of the plurality of logical zones.

30. The SAS topology of claim 24, wherein the virtual domain is defined in accordance with group membership of the plurality of host and target devices.

31. The SAS topology of claim 30, wherein the at least one expander forms a switch fabric having ingress and egress ports.

32. The SAS topology of claim 31, wherein the BPP function associates group membership information to the broadcast primitive upon receipt at an ingress port, and removes the group membership information upon transmittal from an egress port.